Mizuno JPX921 Hot Metal Pro Irons Review

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The Mizuno JPX921 Hot Metal Pro irons are game improvement irons with plenty of ball speed but little offset.  A rare combination that can be great for combo sets.


For the last couple years, I’ve been critical of Mizuno for releasing too many irons that aren’t clearly differentiated.  The biggest exception has been the Hot Metal Pro, which I praised when it was unveiled in 2018.  Does the latest version continue to offer golfers something they can’t find anywhere else?


The Mizuno JPX921 Hot Metal Pro irons are game improvement irons without the offset.  The top line is thinner than expected, and the use of two tones of silver makes it appear even slimmer.  Offset and blade length are the two ways that the Pro model differentiates itself from the standard Hot Metal irons.

In the bag, the JPX921 Hot Metal Pro is nearly identical to the standard Hot Metal.  Both use a black and silver color scheme, eschewing any fancy paint fill colors.  The branding is confined to the cavity and looks sharp.

Sound & Feel

My primary issue with the original Hot Metal Pro irons [review HERE] was the unpleasant feel.  This is been improved markedly in the new version.

Both the JPX921 Hot Metal and the JPX921 Hot Metal Pro irons are made with the same Chromoly metal and feature a frighteningly thin face.  These irons feel very crisp on center but are much quieter than previous iterations.  Neither iron feels soft, but pure strikes do feel solid.

Feedback is about what you’d expect from a game improvement iron.  Misses get dull, losing the crisp snap.  Through the hands, feedback isn’t precise but it’s good enough to get a general idea about how you struck the ball.


What made the original Hot Metal Pro irons so intriguing was the combination of limited offset with forgiveness and ball speed.  That combination is still the main selling point with the JPX921 Hot Metal Pro irons.

On center, these irons are about as fast as anything you can buy.  The Chromoly face is extremely thin which leads to very high ball speeds.  Mizuno is also using a seamless cup face on these irons which helps to retain more ball speed on mishits.  I found that the forgiveness is good, but it’s not a club I would recommend for the higher handicap player.

The JPX921 Hot Metal and Hot Metal Pro have fairly strong lofts which are a key part of how they create so much distance and ball speed.  Strong lofts also lead to lower launch and lower spin.  I found the Hot Metal Pro to be slightly lower launching and spinning than the standard version.  As always, it is critical to be fit for these irons so you can hit the ball a long way and have it hold the green.


Whether you order a full set or just use them to fill out the top end of your bag, the Mizuno JPX921 Hot Metal Pro irons are going to help you hit the ball a long way.  The smaller head and reduced offset give them a look that’s more attractive to better players and makes them ideal for pairing with the JPX921 Forged or Tour.

Mizuno JPX921 Hot Metal Pro Irons Price & Specs

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Matt Saternus

Founder, Editor In Chief at PluggedInGolf.com
Matt is the Founder and Editor in Chief of Plugged In Golf. He's worked in nearly every job in the golf industry from club fitting to instruction to writing and speaking. Matt lives in the northwest suburbs of Chicago with his wife and two daughters.

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  1. My issue with thin faces is they almost seem to give you a diminished return on ball speed the faster you swing. Help slower speeds get higher speed but higher speed seems to overpower the thin face. For instance with the sub70 699 pro vs pxg gen 3 p the sub 70 was almost a full club longer with identical specs and same strike pattern. My 5 iron carry is 210. Would like to see a study done on various swing speeds including tour level speed and see if there is a point of dr.

    • Matt Saternus


      That’s interesting. When you did that head to head test, was it the ball speed that was leading to the difference in distance or launch and spin?


  2. Matt:
    Can you explain the benefit or disadvantage of having or not having an offset. I do not know if not having an offset for these irons is a plus or minus.


  3. Frank Schmieder

    Frank, Bob’s comment sounds as if it defies the laws of physics. It can only happen if the face of the club is decompressing at the moment of impact thetef reducing the ball compression. Usually speed kills .

  4. Man I love the look of these irons. When you say you probably wouldn’t recommend these for high handicappers, about what range of hcp are you referring to, and were you referring to the Hot Metal Pro only or also the regular Hot Metals?


    • Matt Saternus


      This review was strictly about the Hot Metal Pro. I think for a player with a handicap much over 20, there are better options.


  5. paul schofield

    How will combining sets effect the trade in value

  6. Thanks for your review. I read your PXG 0211 review and that’s what I currently play. How would you compare the HMP to the 0211 as far as feel, forgiveness, and distance?

    • Matt Saternus


      I think the 0211 is marginally more forgiving for ball speed. Distance is going to depend on fit and shaft.



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